relative_symlink.rb

require 'pathname'
class File
  def self.relative_symlink(old_file, new_file)
    symlink(relative_path(File.dirname(new_file), old_file), new_file)
  end
  
  def self.relative_path(base_path, file)
    Pathname.new(File.expand_path(file)).relative_path_from(Pathname.new(File.expand_path(base_path))).to_s
  end
end